Thyroid Meds

Hi,

Is it ok to be on really high dose of thyroid meds?  It seems my TSH is very very low, but my FT3 and FT4 are both in low normal range.  I take a combination of Dessicated Thyroid (125 mcg) plus levothyroxine 225 mcg.  I am 6 months pregnant.  I don't seem to have symptoms of being hyper, but my doctor is reluctant to increase thyroid meds much more (we've been increasing the T4 by 25mcg every month since I got pregnant) due to high dose I am currently on and very low TSH.....

Aside: I've never had high antibodies since I was first diagnosed, so this may not be autoimmune..... I do have pituitary microadenoma (about 5mm x 5 mm), but dr. says this is to small to be of concern and is unrelated to thyroid, and other than prolactin testing (which was high), I've never had any pituitary testing done.

Thanks.

S